title: Effect of UV-C on thylakoid arrangement, pigment content and nitrogenase activity in the cyanobacterium Microchaete sp.
abstract: The effect of UV-C radiation on thylakoid arrangement, chlorophyll-a and carotenoid content and nitrogenase activity of the cyanobacterium Microchaete sp. was studied. Chlorophyll-a and carotenoid content increased gradually up to 48 h of UV-C exposure but declined with longer exposures. Nitrogenase activity decreased moderately with 6 to 12 h exposure and decreased substantially afterwards. When cells exposed to UV-C for 12 to 24 h, grown under fluorescent light for 144 h, nitrogenase activity increased to levels greater than in the control cells. The exposure of UV-C treated cells to fluorescent light, however, did not result in recovery of pigment content. In Microchaete sp. cells treated with UV-C for 144 h, thylakoid membranes became dense, were aggregated into bundles, and were surrounded by spaces devoid of cytoplasm.
authors.affiliation: Faculty of Science, University of South Bohemia, Ceské Budejovice, Czech Republic. jayantakumarsahu@yahoo.co.in
authors.forename: J K
authors.initials: JK
authors.lastname: Sahu
authors.forename: M
authors.initials: M
authors.lastname: Simek
mesh_terms: D000458:Cyanobacteria / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D046529:Microscopy, Electron, Transmission; D009591:Nitrogenase / Q000378:metabolism*; D010860:Pigments, Biological / Q000378:metabolism*; D020524:Thylakoids / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D010860:Pigments, Biological; D009591:Nitrogenase